As the longevity of some spacecraft in space has increased with technology to 20 years or more, it has become necessary to replace fluids aboard these spacecraft. Manned servicing has been demonstrated to be one approach to replacing these fluids, but the cost of protecting a man/men from the hostile environs of space is particularly high. For many tasks, unmanned, remotely controlled spacecraft equipped with remote manipulators provide a cost effective alternative to manned servicing, especially when potentially dangerous propellants, such as Hydrazine, are to be transferred from a refueling vehicle to an on-station satellite.
Toward this end, fluid transfer couplings have been designed for use in space, but these couplings have operating requirements which may exceed the capabilities of remote manipulators to connect and disconnect them. For example, one such fluid transfer coupling requires a closing force of 42 pounds to be applied between the two halves of the coupling, a force which may not only exceed the capability of the manipulator, but which would force the two vehicles apart if the only docking connection between them is the fluid coupling. As orbital spacecraft typically are provided with small thrusters which produce only a limited amount of thrust to maintain or change their orbits, it is apparent that the force required to close this coupling would move a satellite out of its orbit, requiring expenditures of fuel to replace it in its selected orbit. In order to overcome this problem, it would be necessary for the refueling spacecraft and the satellite to each be equipped with docking hardware to enable a docked configuration between them. This extra docking hardware is expensive from a manufacturing standpoint and further adds to the respective weights of the vehicles to be lifted from Earth.
In accordance with this invention, the applicants have provided a system for mating fluid transfer couplings which is easily adapted to robotic manipulators, and which further requires only a small amount of torque (two foot-pounds by the robotic manipulator) to close the couplings.